How do I import a Camera from an external .blend file?
You should append the camera from the "Object" Data-Block, not the "Camera" Data-Block.

Shift+F1 to append, select the .blend file and go to the Object Data-Block and select the camera. Then hit "Append from Library".



Update

When you append from the "Camera" Data-Block, you are appending the Camera's settings, not the Camera object itself.



But when you append from the "Object" Data-Block, you'll be appending the camera itself (the object), including it's settings.